The memo's warning to British Prime Minister Tony Blair was stark: his upcoming visit to President Bush's Texas ranch would not be a matter of long barbecues and songs around the campfire.
Instead, the April 2002 visit would involve discussion about a possible war in Iraq. Any decisions taken by the Atlantic allies might prove fateful, warned the memo's writer, British Foreign Secretary Jack Straw.
Mr. Blair's own Labour Party - indeed, the world at large - still needed to be convinced why the threat from Saddam Hussein had suddenly become dire, why an invasion wouldn't contravene international law, and what kind of government might replace the Hussein regime.
"The rewards from your visit to Crawford will be few. The risks are high, both for you and the government," said Mr. Straw.
Two years after a US-led force toppled Mr. Hussein, publication of a series of secret internal British documents known collectively as the "Downing Street memos" is shedding new light on the thinking process in Washington and London in the run-up to war.
To some analysts, these memos document how the White House was intent on war in Iraq only months after the terror attacks of Sept. 11, and manipulated intelligence to fit its preconceptions.
To others, the information in the memos is vague, and their general conclusions are matters that were widely reported at the time.
If nothing else, the memos do provide a rare glimpse into the process of policymaking at top levels, and provide the sort of quotes and conclusions that historians may cite for years to come.
The first internal paper to earn the tag "Downing Street Memo" was published in the Sunday Times of London last month.
This memo summarized a July 23, 2002, meeting of Blair and top advisers. Its most widely reported passages relay the impressions garnered by a senior British intelligence official, Richard Dearlove, on a visit to Washington.
"There was a perceptible shift in attitude. Military action was now seen as inevitable," according to Mr. Dearlove, named in the memo only as "C."
"But the intelligence and facts were being fixed around the policy. The NSC had no patience with the UN route ... There was little discussion in Washington of the aftermath after military action."
Critics say this is a smoking gun, proving that the administration was simply pretending that war might be forestalled during the months prior to the actual invasion, and that it knowingly corrupted intelligence reports to back a policy that was foreordained.
Others have a different reading of this passage. The memo does not say specifically that Mr. Bush, or indeed any US official, saw war as inevitable. And at the time, the media was rife with commentary that war was most likely coming. If seen in that general sense, the conclusion was unsurprising.
Nor did the document offer details of what intelligence was being fixed around what policy. Over the last year, a series of US studies have offered scathing conclusions about the poor nature of prewar US intelligence, and its uses.
A second memo, published in the Times of London on June 12, concluded only that US government military planning for action against Iraq was "proceeding apace."
This memo, produced for British cabinet's consideration at a July 22, 2002, meeting, reiterated the point that the US appeared to have given little thought to a war's aftermath. "In particular, little thought has been given to creating the political conditions for military action, or the aftermath and how to shape it," concluded the memo's uncredited author.
This second document appears to contradict somewhat the insistence of the first that military action was "inevitable." But it was prescient in its view of what might happen in the months after victory. "A postwar occupation of Iraq could lead to a protracted and costly nation-building exercise. As already made clear, the US military plans are virtually silent on this point," said the July 22 cabinet memo.
A series of other leaked memos reported at various times in the British press has added context and supplied detail to these two main papers.
Neither Washington nor London has challenged the authenticity of any of the Downing memos. But both Bush and Blair have said that they do not reflect the full facts of war planning.
As they reflect a uniquely British view of Washington actions, the papers provide interesting insight into the general relationship of two old allies.
The British seemed confident that they have some leverage to influence the Bush administration's course of action. A March 22, 2002, memo from British Foreign Office political director Peter Ricketts claims that by sharing Bush's broad objective, Blair can "help shape how it is defined" and the approach to achieving it. "He can help Bush make good decisions by telling him things his own machine probably isn't," wrote Mr. Ricketts.
Indeed, throughout the memos, the Bush administration is depicted as being dismissive of the need for UN Security Council approval for an Iraq war. The implication is that the final push for a UN stamp of approval was the result of pressure from London.
But the officials drawing up the memos were far from omniscient. An options paper summary notes that, following the invasion, a representative Iraqi government would likely be led by Sunnis, not Iraq's Shitte Muslim majority.
Nor did they rely entirely on quiet lunches and dinners with the inner circle of powerful Washington officials. A March 14 memo from Blair's chief foreign policy adviser, Tony Manning, describes a meal with Condoleezza Rice, then head of the National Security Council, but also refers to an attached article by Seymour Hersh, a New Yorker magazine journalist who helped expose Abu Ghraib prison abuses.